This invention pertains to pressing machines and, in particular, to pressing machines for garments or the like.
Conventional garment pressing machines typically utilize a pivotally mounted lever or arm (y-piece) to move a pressing head into forceful engagement with a pressing surface or support (buck) holding the article to be pressed. In these machines it is customary to first pivot the arm so that the head is closely spaced from or in slight pressure engagement with the buck. Additional force is then applied to the arm so that the head exerts the necessary pressure (e.g., several thousand pounds) on the buck to press the article.
Various pressing machine configurations have been proposed to achieve this pressing action. U.S. Pat. No. 1,797,720 discloses one type machine in which an actuating air cylinder acting through a toggle arrangement provides the initial pivoting of the press arm. The toggle arrangement locks the arm and an expansible fluid filled chamber on the buck is then pressurized to provide the necessary pressing pressure between the head and buck. U.S. Pat. No. 1,797,757 discloses a similar press with an expansible buck, but with a modified arm arrangement. In this case locking of the arm is through engagement of a pawl and ratchet under the pressure created by the expansible buck. An expansible buck type press is also disclosed in U.S. Pat. No. 2,068,643.
In U.S. Pat. No. 3,877,161, on the other hand, the head, rather than the buck, is made expansible and is used to realize the desired pressing pressure.
A further pressing type machine is disclosed in U.S. Pat. No. 4,002,046. In this type machine, a cavity in the buck is selectively pressurized to cause pistons or controlled diaphragm members to urge the buck pressure plate against the pressing head.
Other pressing machine arrangements are also known wherein actuating air cylinders are used to realize both the initial arm pivoting and the desired pressing pressure. In this type of arrangement, a small-bore cylinder provides the initial pivoting under relatively little pressure, while a large-bore cylinder provides pressing action under relatively heavier pressure. Usually, the large-bore cylinder is located such that the cylinder goes over the bottom dead center at some point during the initial pivoting of the arm. In this way, the amount of stroke required of the large-bore cylinder to permit the full motion of the arm is reduced. However, the required stroke is still much longer than that which would be required to provide the slight additional movement of the arm to result in the desired heavy pressure. The large-bore cylinder must, therefore, consume a significant quantity of air which produces no useful result.
The necessity of using a large-bore long-stroke cylinder in the aforesaid pressing machine thus presents disadvantages from both an operational and economic point of view. Furthermore, the other described pressing machines suffer disadvantages of one type or another.
It is a primary object of the present invention to provide a pressing machine of an improved type.
It is a further object of the present invention to provide a pressing machine in which initial pivoting and pressing are realized in an operationally and economically efficient manner.